Transmen are four or five times as likely as females in general to suffer a heart attack.
A 2019 study  found that post-operative female-to-male transgender people were 4.9 times as likely to suffer a myocardial infarction (heart attack) than women in general.
Another study  also found a somewhat smaller yet still large discrepancy, concluding that transmen were 3.69 more likely to suffer a heart attack than women in general.
 Alzahrani, T. Nguyen, T., Ryan, A., Dwairy, A. McCaffrey, J., Yunus, R., Forgione, J., Krepp, J., Nagy, C., Mazhari, R. & Reiner, J. (2019). Cardiovascular Disease Risk Factors and Myocardial Infarction in the Transgender Population. Circulation: Cardiovascular Quality and Outcomes 12 (4). [Link]
 Nota, N.M., Wiepjes, C.M., de Blok, C.J.M., Gooren, L.J.G., Kreukels, B.P.D. & den Heijer, M. (2019). Occurrence of Acute Cardiovascular Events in Transgender Individuals Receiving Hormone Therapy: Results From a Large Cohort Study. Circulation 139: 1461-1462. [Link]